This invention constitutes an improvement over the assemblies as disclosed in U.S. Pat. Nos. 3,877,203 and 4,143,503. The disclosures of these earlier patents are specifically incorporated herein to further set forth the manner in which the various parts operate with respect to each other.
The wrapping machines in which the present assembly may be moved operate at speeds of up to 200 packages per minute and function on an intermittent basis, thus a working operation is effected at different work stations along the the path of movement for each article. During the moment of time that the packages are stationary at each work station, a separate wrapping function is possible. The use of a conveyor mechanism as set forth in the prior art enables the folding of the wrapping sheet in a flat plane while the article is stationary. This provides a faster and more reliable wrapping function than is presently available in the round turret type wrapper mechanism.
Prior art wrapping machines use the standard conveyor chain to connect carrier blocks for pockets which contain the articles being moved along a path. Wear of the standard chain links due to the stress at the speed of operation has been a continuing problem. Standard sprocket wheels used in prior art machines are designed to be in contact with eack link of the standard chain link conveyor. Because of the nature of the wrapping process, extreme amounts of wear occur on the sprocket and the chain. As the chain moves around the sprocket wheel, the chordal distances is necessarily greater than the length of the chain required to move the pocket members in a flat or linear direction. This continues changing of stresses contributes heavily to the wear and loading on the individual links.